[PATCH v5 -next 07/11] PCI: brcmstb: Adjust PHY PLL setup to use a 54MHz input refclk
Bjorn Helgaas
helgaas at kernel.org
Fri Feb 21 13:33:11 PST 2025
On Mon, Jan 20, 2025 at 03:01:15PM +0200, Stanimir Varbanov wrote:
> The default input reference clock for the PHY PLL is 100Mhz, except for
> some devices where it is 54Mhz like bcm2712C1 and bcm2712D0.
>
> To implement this adjustments introduce a new .post_setup op in
> pcie_cfg_data and call it at the end of brcm_pcie_setup function.
>
> The bcm2712 .post_setup callback implements the required MDIO writes that
> switch the PLL refclk and also change PHY PM clock period.
>
> Without this RPi5 PCIex1 is unable to enumerate endpoint devices on
> the expansion connector.
This makes it sound like this patch should be reordered before "[PATCH
v5 -next 06/11] PCI: brcmstb: Add bcm2712 support".
We don't really want a driver to claim a bcm2712 controller before
it's able to enumerate devices, because that would break bisection
through this.
Bjorn
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